Collectible coins are often categorized based on their historical significance, rarity, condition, and demand among collectors. In the United States, coins such as the Fifty Cents, often referred to as half dollars, feature iconic designs and can vary in value based on mint marks and production years. The Flying Eagle Cent, minted from 1856 to 1858, is notable for its distinctive design featuring an eagle in flight and is considered a key date in the series of small cents, appealing to numismatists due to its limited mintage and historical context.